Dust shield for use with a motion transmitting rod

ABSTRACT

A device for adjustably positioning a structural element in a dust-laden environment, such as for positioning impact casing elements in a metallurgical blast furnace, consists of a motion rod connected between a drive member and the elements to be positioned and a shield through which the motion rod extends, the shield is constructed of plates which form a slot and of a slide movably positioned in the slot and having a bore through which the motion rod extends. The slide covers an opening through the plates and forms a closure against the passage of dust into the drive member. Further, the bore surface through the slide is shaped to afford not only longitudinal movement of the motion rod but also limited pivotal movement and, in addition, the slide affords transverse movement.

United States Patent Rumping Nov. 19, 1974 Appl no; 291,409

DUST SHIELD FOR USE WITH A MOTION TRANSMITTING ROD Inventor: Stephanus Nicolaas Hendrick Rumping, Beverwijk, Netherlands Gutehoifnungshutte Sterkrade Aktiengesellschaft, Oberhausen, Netherlands Sept. 22, 1972 Assignee:

Filed:

Foreign Application Priority Data Sept. 21, Ci ermany 2147123 US. Cl. 266/25, 266/27 Int. Cl C21b 7/02 Field of Search 214/36, 37; 266/25, 27,

References Cited UNITED STATES PATENTS ll/l96l Tsujihata et al. 214/36 X Primary Examiner-Gerald A. Dost Attorney, Agent, or FirmToren, McGeady and Stanger [5 7] ABSTRACT A device for adjustably positioning a structural element in a dust-laden environment, such as for positioning impact casing elements in a metallurgical blast furnace, consists of a motion rod connected between a drive member and the elements to be positioned and a shield through which the motion rod extends, the shield is constructed of plates which form a slot and of a slide movably positioned in the slot and having a bore through which the motion rod extends. The slide covers an opening through the plates and forms a closure against the passage of dust into the drive member. Further, the bore surface through the slide is shaped to afford not only longitudinal movement of the motion rod but also limited pivotal movement and, in addition, the slide affords transverse movement.

PATENTED MW 1 91914 3'. 848,861

SHEEF 2 OF 2 Z z? 27 is ""2! 24 W FlCJbb DUST SHIELD FOR- USE WITH A MOTION I TRANSMITTING ROD SUMMARY OF THE INVENTION The present invention is directed to a device used for adjusting a structural element in a dust-laden environment, and, more particularly, it is directed to a shield for a motion rod which prevents passage of dust from the environment containing the structural elements to the drive member for the motion rod.

In dust-laden environments it is often necessary to adjustably postion a structural element, such as the impact casing elements used in a metallurgical blast furnace, and a motion rod is provided between the structural elements and a drive member to afford not only longitudinal movement of the motion rod but also a limited pivotal and/or transverse movement in at least one direction. The present invention is concerned with the provision of a dust shield for the motion rod for limiting the passage of dust along the motion rod toward its drive member.

It is often necessary to operate movable parts within a dust-laden space. Special precautions are necessary to protect the drive members which produce the mo tion of the parts against fouling or malfunction due to the adverse effect of the dust present in the space where the part-operates. If the motion is a pure longitudinal motion or a pure-rotational motion about its own axis, it is sufficient in most instances to provide around the member or rod which transmits the motion, a simple dust-reversing device. However, difficulties arise when the structural elements must execute combined movements including not only a longitudinal movement but also a limited pivotal and/or transverse movement in at least one direction.

Such a situation exists in an adjustable impact casing for use in a metallurgical blast furnace. Accordingly, the present invention will be described with reference to its use in positioning the structural elements of an impact casing in a metallurgical blast furnace, though the invention'is not limited to such an application and can be used in a similar manner in other fields of technology. It is customary to charge a blast furnace from the top through a port which can be opened betweena fixed seat and a bell adjustable in the vertical direction. When the port is opened, the charge falls into the blast furnace sloping radially outwardly along the upper surface of the bell. As a result, there is danger of serious damage to the blast furnace lining. Accordingly, it has been proposed in the past to shield the lining of the furnace in the charging zone by means of a fixed or adjustable impact casing made up of a number of separate elements. The adjustment of the impact casing elements is effected by means of motion rods which extend inwardly through the furnace shell into connection-to the elements. Therefore, the ore dust" and of the impact casing element to which it is coupled. To eliminate the problem of dust entering the drive member, it has been proposed to position a kind of apron around the motion rod between the furnace chamber and the drive member so that the apron prevents the penetration of most of the dust into the drive member. Although such a device has had'some success, it has been found that ultimately fouling of the drive member cannot be prevented. However, in accordance with the present invention, a shielding arrangement has been conceived which makes it possible to eliminate, almost completely, the disadvantages which arise when dust enters into the drive member.

In accordance with the present invention, the dust shield consists of a plate type slide having a bore through which the motion rod extends and with the surface of the bore providing the least possible clearance about the motion rod. The slide is displaceably guided within a slot formed by two fixed plates which are spaced apart by the thickness of the slide. At least one of the fixed plates forms a partial closure of the passage between the impact casing element and the drive member. The remaining opening through the dust shield is closed in every possible position of the motion rod by the slide. Due to the arrangement of the dust shield, its sealing function is provided by two features, the longitudinal movement and slight pivotal movement of the motion bar is made possible by the arrangement'of the bore through the slide, the surface of the bore being shaped to provide such a small clearance about the motion rod that almost a complete barrier is provided against the penetration of dust in the direction of the drive member. Further, the transverse movement of the motion rod is made possible by the sliding movement of the slide in the slot provided by the fixed plates of the shield. The slot formed by the plates also provides a barrier against the penetration of dust in the direction of the drive member. By providing two different slotlike arrangements for accommodating the different movements of the motion rod, ithas been possible to make each slot-like arrangement considerably narrower and thereby restrict the flow of dust along the motion rod toward the drive member.

For the movement of a rod through a hole where pivotal movement is also to be possible, the opening or bore in the slot should have a greater dimension'than the transverse dimension of the motion rod. However, the opening through the slide can be retained at a minimal amount if the surface of the bore has a suitable form. Specifically, the preferred configuration of the surface forming the bore would theoretically consist of two serially arranged frusto-conical surfaces with the half apex angle corresponding to the maximum deflection of the motion rod.'ln practice it has been found, however, that it is preferable if the surface of the bore extending inwardly from the faces of the slide are frusto-conically shaped and converge inwardly toward one another in the direction of the bore axis and, further,

at the point of the least dimension of the bore its surface between the frusto-conically shaped surfaces has a radius of curvature which is less than 20% of the motion rod diameter. In addition, it is possible to fit the slide around its entire peripheral edge into a slot. In suchan arrangement the slide could have a circular periphery, but since one of the movements of the motion rod in the transverse direction will be considerably greater than its movement in the other transverse direction, it has proved advantageous to provide the slide with a mainly rectangular form and to fit it into two slots formed by the fixed plates of the shield and extending along the two longer sides of the rectangularly shaped slide. In such an arrangement the slots can be straight so that a simple construction is obtained.

As an additional feature for preventing the passage of dust into the drive member, the present invention includes means, located on the drive member side of the shield, for maintaining a gas overpressure relative to the furnace side of the shield. Because of the small transverse dimensions of the slotted openings, it is possible to maintain a sufficiently high gas velocity at a very small gas overpressure through the slotted openings counter to the normal direction of passage of the dust, for maintaining the slotted openings entirely free of dust. If the invention is used with a blast furnace, an overpressure on the drive member side of the shield can be successfully maintained with purified blast furnace gas or natural gas. Accordingly, any gas which leaks through the shield into the blast furnace then corresponds, in composition, to the gas atmosphere within the blast furnace or even enrichs it.

In one possible arrangement, the drive member for the motion rod is located within a hood which, in turn, is secured to the blast furnace shell and the shield for the motion rod is secured within the hood. For reasons of assembly, however, a preferred arrangement consists of a hollow beam secured to the blast furnace shell and extending into its refractory furnace lining with the shield forming an end face of the hollow beam outwardly from the furnace shell. A hood encloses the drive member and extends inwardly to and at least a portion of the hood is detachably secured either directly or indirectly to the shell of the blast furnace.

Therefore, when installing the device embodying the present invention, it is possible first to install the hollow beam with the dust shield and then to add the drive member within its surrounding hood. Moreover, in this arrangement the hollow beam can provide a support for the refractory material lining the furnace shell. Because the hood enclosing the drive member is partially detachable, the condition of the dust shield can be checked periodically without affecting the operation of the furnace. Additionally, any small amounts of dust which have penetrated through the shield can be removed in a simple manner.

Another preferred feature of the shield arrangement is the construction of the slide from two plate-like members each having a U-shaped recess along one side. This arrangement facilitates the assembly and disassembly of the slide. With this construction, the two parts of the slide can be arranged about the motion rod after it is installed and then can be firmly connected together. Naturally, the slide constructed of two parts should be sufficiently flat for easy movement in the slots within the shield without forming any larger openings.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a more or less schematic vertical sectional view of a portion of an adjustable impact casing in a blast furnace embodying the present invention;

FIG. 2a is an enlarged detail view of the encircled portion of FIG. I designated II;

FIG. 2b is a sectional view of a portion of FIG. 2a indicating a different arrangement due to a different position of the impact casing; V

FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 20;

FIG. 4 is a view, partly in section, taken along the line IVIV in FIG. 2b;

FIG. 5a is an enlarged view of a portion of the ar- DETAILED DESCRIPTION OF THE INVENTION In FIGS. 1, 2a and 3, the steel shell 1 of a blast furnace is shown coated with a refractory lining 2. As indicated by FIG. 1, the portion of the blast furnace shell shown in the drawing is located in the vicinity of the lower filling bell 3 which, as indicated by the arrow, can be moved vertically in the direction toward and away from the fixed seat 4. As shown in FIG. 1, the bell 3 is spaced downwardly from the fixed seat 4 forming an opening or port through whic the blast furnace charge can flow downwardly as indicated by the arrows.

After passing through the port between the bell 3 and the fixed seat 4, the charge is directed against the cast steel impact casing segments 6 which are suspended by hooks 7 and 8 in openings in steel plate 9. For example, in the impact casing there are twenty of the segments 6 in a ring-shaped arrangement overlapping one another on the inside or outside in the path of the charge through the port 5. The steel plate 9 forms a part of a suspension construction which includes two cross-stays l0 and a pendulum bar 11. As indicated by the arrows, the pendulum bar 11 can be moved inwardly and outwardly relative to the shell 1 about a pivot, not shown, so that the shell elements or segments 6 follow a similar path of movement.

For effecting the movements of the elements of the impact casing, the head of a motion bar 14 is secured between the stays l0 and two cross-bridges 12, 13. The motion bar 14 is moved back and forth in the direction of the arrow by means of a drive box 15 whereby the position of the casing segments can be set.

Dust from within the furnace is prevented from passing into the drive box by a shield 16 laterally arranged about the motion rod 14. In FIG. 2a an enlarged view of the shield 16 is shown. Disposed about and spaced outwardly from the motion rod 14 is a hollow beam 17 of rectangular cross-section. The hollow beam 17 is spaced inwardly from the drive box 15 and is secured to the shell separately from the drive box. While, as shown in FIG. 2a, the drive box is secured to the outer surface of the shell 1, the hollow beam extends into the refractory lining 2 of the furnace and forms a support for the lining. At its end spaced outwardly from the shell 1, the opening through the hollow beam is partly closed by a plate 18 having a centrally arranged opening 22. Fastened to the plate 18 by means of bolts 21 are two sectional beams 19 and a portion of the beams 19 are spaced from the plate 18 providing two slots in which a plate-type slide 20 is movably positioned. The plate-type slide has an aperture or bore through which the motion bar 14 passes. The bore in the slide 20 fits, as tightly as possible, around the motion bar 14, without impeding its movement in the longitudinal direction. To allow for a slight pivotal rotation of the motion bar, the surface of the bore is frusto-conical from the opposite sides of the bore inwardly toward the center, and the center surface portion of the bore does not form an apex but rather is rounded in a semicircular manner.

In FIG. 2b, the position of the motion bar 14 and of the slide 20 is different from that in FIG. 2a due to the movement of the impact casing elements or segments 6. Therefore, it is evident that the slide by virtue of its bore permits both a longitudinal movement and a pivotal movement while the movement of the slide within the slots formed in the shield permits a transverse movement of the motion rod. During all of these various movements of the rod there is no appreciable opening between the slide and the motion rod. Accordingly, an effective shield is provided which prevents the passage of dust along the motion rod 14 into the interior of the drive member or housing 15.

In FIG. 3, which is a transverse section of the showing in FIG. 2a, it is evident that the slide 20 can be moved in a direction across the direction of movement of the motion rod shown in FIG. 2b. Accordingly, two extreme positions of the motion rod 14, 14a and of the slide 20 and 20a are shown in solid lines and broken lines respectively. These extreme positions areattained by means of a crank mechanism which is designated schematically by the povot point 21a. In FIG. 4, a transverse section is shown of the arrangement in FIG. 2b and it is evident that the plate-shaped slide 20 always covers the opening 22 in the plate 18 regardless of the manner in which the motion rod is moved across the opening 22 in the transverse direction. Further, the slide always remains closed in that portion in contact with the beams 19.

Optionally, the bottom of the lower sectional beam 19 can be provided with downwardly extending openings for discharging any dust which might gradually accumulate in the slot below the slide 20.

In FIGS. 5a and 5b, the plate-shaped slide 20 is illustrated in detail. As shown, the slide is made up of two parts 23, 24 which can be fastened together by screws extending through holes 26 into the tapped holes 23. Each of the two parts 23, 24 have a pair of tongue-like portions 27, 28 each of which has a thickness which is half that of the thickness of the plates 23, 24. In combination with the plates 23, 24 the tongue-like portions 27, 28 form a U-shaped recess in the sides of the plates which face toward one another. When the two plates 23, 24 are fitted together, the U-shaped recesses form a circular hole having a semi-circular rounded edge, as shown in FIG. 2a. By this arrangement it has been found that a shield is formed which is sufficiently safe against the penetration of dust from the blast furnace into the drive box or housing 15.

Based on this dust shield arrangement, numerous variations are possible within the scope of the invention. Accordingly, it is possible, for example, to develop the drive of the motion rod 14 by means other than a crank mechanism, for instance, by means of a gear quadrant and gear rack or by hydraulic means.

Further, it is possible, for example, rather than fastening the drive housing directly to the furnace shell to attach it by means of a flange connection on plate 18. However, in such an arrangement the plate would be made somewhat larger.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be under stood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A device for adjusting the position of a structural element in a dust-laden environment, such as for use inside of a metallurgical blast furnace, including a drive member, a passageway extending from said drive member toward said structural element, an axially elongated motion rod extending through said passageway between said drive member and said structural element, said motion rod being capable of effecting the combination of longitudinal movement and limited pivotal movement and/or transverse movement in at least one direction, means for preventing the passage of dust along said motion rod toward said drive member, wherein the improvement comprises that said means for preventing the passage of dust includes a shield having an opening therethrough, said shield extending transversely of said motion rod and across said passageway so that flow through said passageway is limited to the opening through said shield, a plate-shaped slide movably displacebly mounted in said shield and extending transversely of said motion rod, said slide closing the opening through said shield, said slide having a bore therethrough so that said motion rod extends through the bore, the bore in said motion rod shaped to conform to the transverse configuration of said motion rod with the minimum clearance therebetween, and said slide closing the opening through said shield in every position of said motion rod so that there is no opening through said passageway through which dust can pass.

2. A device, as set forth in claim 1, wherein said shield comprises a plate means arranged to form a slot therebetween extending transversely of the axis of the said motion rod, and said slide being movably displaceable through said slot.

3. A device, as set forth in claim 2, wherein said plate means comprises a first plate forming the opening closed by said slide, and at least one second plate fixed to said first plate with portions of said first and second plates spaced apart by a dimension equal to the thickness of said slide and forming said slot for said slide therebetween.

4. A device, as set forth in claim 1, wherein the surface of the bore through said slide has an axially extending frusto-conically shaped portion extending from each of the opposite faces of said slide so that the surfaces converge toward one another inwardly toward the center portion of the bore, and a rounded portion of said bore surface interconnecting the frustoconically shaped portions.

5. A device, as set forth in claim 4, wherein the rounded portion of said bore between the frustoconically shaped portions thereof has a radius of curvature which is less than 20 percent of said motion rod diameter.

6. A device, as set forth in claim 3, wherein said slide having a generally rectangular form in the plane transverse to the axis of said motion rod and two of the sides of said slide being arranged in a sliding fit in said slot formed by said first and second plates.

7. A device, as set forth in claim 6, wherein said slide comprises a pair of plate-like members each having a U-shaped recess in one side thereof, and means for removably securing said plate-like members together so that the U-shaped recesses combine to form the bore through said slide.

8. A device, as set forth in claim 7, wherein each of said plate-like members of said slide has a pair of said tongue-like portions.

9. A device, as set forth in claim 1, wherein means are provided for maintaining a gas over-pressure within said passageway on the side of said shield closer to said drive member.

10. A device, as set forth in claim 1, wherein said structural elements are adjustable impact casing members for a metallurgical furnace and at least a number of said impact casing members being connected each to a different said motion bar.

11. A device, as set forth in claim 10, wherein a refractory lining for the metallurgical furnace, said passageway extending between said drive member comprising a hollow beam enclosing said shield at one end thereof and extending inwardly therefrom into said refractory lining, and an at least partially detachable hood member laterally enclosing the end of said hollow beam and shield and extending inwardly therefrom to the outer surface of the metallurgical furnace, said hood member enclosing said drive member.

I UNITED STATES PATENT OFFICE -CERTIFICATE OF CORRECTION Patent No. 3,848,861 Dated November 19, 1974 In ab Stephanus Nicolaas Hendrick Rumnin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In'the heading of the patent, the name and country of the assignee should read:

"[73] Assignee: Gutehoffnungshfltte Sterk-rade Aktiengesellschaft, Oberhausen,

Germany Signed and sealed this 21st day of January 1975.

(SEAL) Attest:

MCCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents :ORM po'mso (069) USCOMM-DC scan-ps9 U. 5. GOVERNMENT PRINTING OFFICE ll, 0-366-33L 

1. A device for adjusting the position of a structural element in a dust-laden environment, such as for use inside of a metallurgical blast furnace, including a drive member, a passageway extending from said drive member toward said structural element, an axially elongated motion rod extending through said passageway between said drive member and said structural element, said motion rod being capable of effecting the combination of longitudinal movement and limited pivotal movement and/or transverse movement in at least one direction, means for preventing the passage of dust along said motion rod toward said drive member, wherein the improvement comprises that said means for preventing the passage of dust includes a shield having an opening therethrough, said shield extending transversely of said motion rod and across said passageway so that flow through said passageway is limited to the opening through said shield, a plate-shaped slide movabLy displacebly mounted in said shield and extending transversely of said motion rod, said slide closing the opening through said shield, said slide having a bore therethrough so that said motion rod extends through the bore, the bore in said motion rod shaped to conform to the transverse configuration of said motion rod with the minimum clearance therebetween, and said slide closing the opening through said shield in every position of said motion rod so that there is no opening through said passageway through which dust can pass.
 2. A device, as set forth in claim 1, wherein said shield comprises a plate means arranged to form a slot therebetween extending transversely of the axis of the said motion rod, and said slide being movably displaceable through said slot.
 3. A device, as set forth in claim 2, wherein said plate means comprises a first plate forming the opening closed by said slide, and at least one second plate fixed to said first plate with portions of said first and second plates spaced apart by a dimension equal to the thickness of said slide and forming said slot for said slide therebetween.
 4. A device, as set forth in claim 1, wherein the surface of the bore through said slide has an axially extending frusto-conically shaped portion extending from each of the opposite faces of said slide so that the surfaces converge toward one another inwardly toward the center portion of the bore, and a rounded portion of said bore surface interconnecting the frusto-conically shaped portions.
 5. A device, as set forth in claim 4, wherein the rounded portion of said bore between the frusto-conically shaped portions thereof has a radius of curvature which is less than 20 percent of said motion rod diameter.
 6. A device, as set forth in claim 3, wherein said slide having a generally rectangular form in the plane transverse to the axis of said motion rod and two of the sides of said slide being arranged in a sliding fit in said slot formed by said first and second plates.
 7. A device, as set forth in claim 6, wherein said slide comprises a pair of plate-like members each having a U-shaped recess in one side thereof, and means for removably securing said plate-like members together so that the U-shaped recesses combine to form the bore through said slide.
 8. A device, as set forth in claim 7, wherein each of said plate-like members of said slide has a pair of spaced tongue-like portions each extending along an opposite side of the U-shaped recess for a dimension at least equal to the depth of the U-shaped recess from the side in which it is formed, each said tongue-like portion having a thickness approximately one-half of that of the remainder of said plate-like members, said tonguelike portions having openings therethrough arranged to align with openings in the other said tongue-like portions of the other said plate-like member, and means for removably securing said plate-like members comprising screws removably secured in the openings in said tongue-like portions.
 9. A device, as set forth in claim 1, wherein means are provided for maintaining a gas over-pressure within said passageway on the side of said shield closer to said drive member.
 10. A device, as set forth in claim 1, wherein said structural elements are adjustable impact casing members for a metallurgical furnace and at least a number of said impact casing members being connected each to a different said motion bar.
 11. A device, as set forth in claim 10, wherein a refractory lining for the metallurgical furnace, said passageway extending between said drive member comprising a hollow beam enclosing said shield at one end thereof and extending inwardly therefrom into said refractory lining, and an at least partially detachable hood member laterally enclosing the end of said hollow beam and shield and extending inwardly therefrom to the outer surface of the metallurgical furnace, said hood member enclosing said drive member. 